vm: remove alt.stack

It is no longer present in NEO3.

pkg/compiler/vm_test.go

@@ -51,7 +51,6 @@ func evalWithArgs(t *testing.T, src string, op []byte, args []stackitem.Item, re
 
 func assertResult(t *testing.T, vm *vm.VM, result interface{}) {
 	assert.Equal(t, result, vm.PopResult())
-	assert.Equal(t, 0, vm.Astack().Len())
 	assert.Equal(t, 0, vm.Istack().Len())
 }
 

pkg/vm/context.go

@@ -32,9 +32,6 @@ type Context struct {
 	// Evaluation stack pointer.
 	estack *Stack
 
-	// Alt stack pointer.
-	astack *Stack
-
 	static    *Slot
 	local     *Slot
 	arguments *Slot

pkg/vm/vm.go

@@ -70,7 +70,6 @@ type VM struct {
 
 	istack *Stack // invocation stack.
 	estack *Stack // execution stack.
-	astack *Stack // alt stack.
 
 	refs *refCounter
 
@@ -100,7 +99,6 @@ func NewWithTrigger(t trigger.Type) *VM {
 	}
 
 	vm.estack = vm.newItemStack("evaluation")
-	vm.astack = vm.newItemStack("alt")
 
 	vm.RegisterInteropGetter(getDefaultVMInterop)
 	return vm
@@ -142,11 +140,6 @@ func (v *VM) Estack() *Stack {
 	return v.estack
 }
 
-// Astack returns the alt stack so interop hooks can utilize this.
-func (v *VM) Astack() *Stack {
-	return v.astack
-}
-
 // Istack returns the invocation stack so interop hooks can utilize this.
 func (v *VM) Istack() *Stack {
 	return v.istack
@@ -264,7 +257,6 @@ func (v *VM) Load(prog []byte) {
 	// Clear all stacks and state, it could be a reload.
 	v.istack.Clear()
 	v.estack.Clear()
-	v.astack.Clear()
 	v.state = noneState
 	v.gasConsumed = 0
 	v.LoadScript(prog)
@@ -281,7 +273,6 @@ func (v *VM) LoadScript(b []byte) {
 func (v *VM) LoadScriptWithFlags(b []byte, f smartcontract.CallFlag) {
 	ctx := NewContext(b)
 	ctx.estack = v.estack
-	ctx.astack = v.astack
 	ctx.callFlag = f
 	v.istack.PushVal(ctx)
 }
@@ -319,9 +310,6 @@ func (v *VM) PopResult() interface{} {
 // Stack returns json formatted representation of the given stack.
 func (v *VM) Stack(n string) string {
 	var s *Stack
-	if n == "astack" {
-		s = v.astack
-	}
 	if n == "istack" {
 		s = v.istack
 	}
@@ -1304,7 +1292,6 @@ func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err erro
 				newEstack.Push(elem)
 			}
 			v.estack = newEstack
-			v.astack = v.Context().astack
 		}
 
 	case opcode.NEWMAP:

pkg/vm/vm_test.go

@@ -149,7 +149,6 @@ func TestPushBytes1to75(t *testing.T) {
 		errExec := vm.execute(nil, opcode.RET, nil)
 		require.NoError(t, errExec)
 
-		assert.Equal(t, 0, vm.astack.Len())
 		assert.Equal(t, 0, vm.istack.Len())
 		buf.Reset()
 	}